Where heavy wood construction is required such as on the planking of boardwalks, docks, walkways, ramps and the like, the specification for the job frequently requires that the planks be nailed in such manner that the nail heads are recessed below the surface of the planks. The recessing is desirable to prevent accidents when people walk across the structure should the nail heads work their way out so as to protrude above the surface of the planking.
Planking for heavy duty use is usually made of very dense wood known in the industry as "green hard lumber." Such lumber presents great difficulty when nails or spikes have to be driven through it. As a consequence, pneumatic hammers are employed to drive the nails through pre-drilled bores which are of a diameter slightly smaller than the diameter of the nails or spikes. The pre-drilled bores are thereafter countersunk by means of a suitable cutting tool to receive the head as it is recessed below the surface of the plank.
In the present state of the art the nails are driven into the bores until the head of the nail is flush with the surface of the plank. Thereafter, the nail heads are recessed manually by workmen using a drive pin and a hammer to force the nail against the bottom of the countersunk portion of the bore. This recessing operation is extremely time consuming and, therefore, adds substantially to the cost of construction.
Accordingly, it is an object of the present invention to provide a nail or spike recessing device which can drive the said spike to a position within a countersunk hole rapidly and accurately. Another object of the present invention is to provide a nail recessing device which is compatible with presently known pneumatic hammers or similar nail driving mechanisms. A further object of the present invention is to provide a nail recessing device which can be quickly removed for repair or replacement without costly interruption of the nailing operation.